Valve-motion for steam-engines



UNITED STATES PATENT IPFICE,

JOHN BUTLER, OF DUNMORE, PENNSYLVANIA.

'VALVE-MOTION FOR STEAM-ENGINES.

Specification of Letters Patent No. 16,227, dated December 16, 1856.

To all whom 'it may concer/n: V

Be it known that I, JOHN BUTLER, of

Dunmore, in the county of Luzerne and.

State of Pennsylvania, have invented a new and Improved Valve-Motion for Steam- Engines; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawing, forming part of this specilication, said drawing exhibiting a side View of the principal working parts of a steam-engine with the improved valve-motion applied.

The invention consists in a certain ar rangement of eccentrics, rock-shafts, rockers and a yoke or its equivalent, applied to actuate a slide valve so as to make it serve both as an induction and eduction valve and a variable cut oft.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

M, is the main framing of the engine, A, is the steam cylinder, B, is the valve seat, and C, the slide valve, which need not differ from the slide valves generally used. The stem a, of this slide valve is made long and furnished with a yoke-frame b, and has stationary guides 7), p', provided for it.

D, is a light framing erected on the main frame M, of the engine to carry the bearings for two rock shafts E and F, which are arranged parallel with each other one below the other. The rockshaft E, is furnished with an arm e, which connects with the rod G', of an eccentric Gr, on the crank shaft S, of the engine, and the rockshaft F, is furnished with an arm f, which connects with the rod H', ot another eccentric H, on the crank shaft.

The rockshaft E, is furnished with a rocker g, which carries a stud g', which plays within the yoke frame o. The yoke frame is of such width that as the rocker is moved by the action of the eccentric Gr, the stud g', will make the greater part of its movement in either direction within the yoke frame without touching it, and then striking one end of it, will move it and the valve rod far enough for the valve to open the port s, or s', to admit steam to the cylinder, said movement thus taking place during a very small portion of the revolution of the crank shaft, and the eccentric Gr, being set in such relation to the crank that the said motion commences as the piston terminates its stroke, and is completed shortly after the commencement of the return stroke.

The rock shaft F, is furnished with a rocker 7L, carrying a stud 7L", which, by the action of the eccentric H, is caused t-o play within the yoke frame ZJ, in a similar manner to tlfe stud g', of the rocker g. This stud when it strikes the yoke moves the valve far enough back from the position to which it has been previously moved by the st-ud g', connected with the other rockshaft and eccentric, to cover the port s, or s, and cut o the steam from the cylinder, but not ifar enough to open the opposite port which remains closed until the rocker g and its stud g', operate on the yoke frame.

The operation proceeds in the above manner, the eccentric Gr, rockshaft E, rocker g, and stud g operating on the yoke to move the valve in either direction to open one of the ports to admit steam to one side of the piston, and the other eccentric H, rockshaft F, rocker z, and stud h', operating on it to move the valve back again only far enough to cut oiti the steam, leaving` the movement which is necessary to open the other port to admit steam on the other side of the piston to be completed by the eccentric G, rockshaft E, rocker g, and stud g. By the abovedescribed operation, a very quick movement is given'to the valve in opening and closing and the ports are allowed to remain wide open during as much or' the stroke as desired.

The variation in the time of cutting oil the steam is toI be ellected generally, by moving the eccentric H farther forward or backward, relatively to the crank on the shaft- S. A slight variation may however be eiiected by shifting the stud in the arm f, on which the hook of the eccentric rod H', catches, nearerto or farther from the rockshaft F, in a slot provided for the purposethereby varying the length of stroke of the stud 7L.

Instead of using a yoke frame b the valve rod may be furnished with lugs corresponding in position with the ends of the yoke frame, the studs g, and L, of the rockers to play between said lugs in the same manner as within the yoke frame. This is an equivalent of the yoke frame.

I do not claim the use of two eccentrics to give the Valve two distinct movements to valve stem said rockshafts deriving motion admit and cut off the steam. But

What I claim as my invention and desire to secure by Letters Patent, s-

The arrangement of the two rockshafts E, F, with their rockers operating upon a yoke Z), or its equivalent7 attached to the from separate eccentrics and the Whole operating substantially as herein described.

`JOHN BUTLER. Witnesses:

' JOHN B. SMITH,

THOMAS B. CLARK. 

